甲硫氨酸诱发高同型半胱氨酸血症对内皮细胞的损伤作用

目的　观察甲硫氨酸诱发高同型半胱氨酸血症对内皮细胞的损伤作用。方法　将 18只新西兰白兔 ,随机分为甲硫氨酸组 (9只 )和对照组 (9只 )。分别喂予添加 3%甲硫氨酸的饲料和普通颗粒饲料 ,第 16周末 ,取血和留取主动脉进行指标测定。结果　甲硫氨酸组血清甲硫氨酸和同型半胱氨酸浓度显著高于对照组 (P <0 .0 1) ,血浆内皮素和血管性血友病因子浓度显著高于对照组 (P <0 .0 1) ,而血浆一氧化氮含量和动脉一氧化氮合酶活性显著低于对照组 (P <0 .0 1) ,主动脉尚未剥脱的和明显损伤的内皮细胞血管性血友病因子表达均明显少于对照组。结论　短期喂食甲硫氨酸诱发高同型半胱氨酸血症 ,即使尚未引起明显的内膜增厚和脂质沉着 ,对血管内皮细胞的功能和结构也有显著的损伤作用。

Injurious effects of hyperhomocysteinemia induced by methionine rich diet on endothelial cells

Objective To observe the injurious effects of hyperhomocysteinemia induced by methionine rich diet on endothelial cells.Methods Eighteen New Zealand rabbits were randomized as methionine group(n=9) and control group(n=9).The control group was fed with ordinary feed and the methionine group was fed with the feed and supplementary methionine (600 mg/d).By the end of sixteen weeks the animals were sacrificed and the blood and aorta were taken for measurements.Results Compared with the control group,the serum levels of methionine and homocysteine were significantly higher (26.44±3.95)μmol/L vs.(14.46± 2.24) μmol/L;(17.89±3.21)μmol/L vs.(9.65±3.56)μmol/L respectively (P< 0.01)], activity of von Willebrand Factor and level of endothelin in blood were significantly increased (135.03±17.47)% vs. (93.41 ±10.35)%,(172.00±18.86) ng/L vs.(96.79±13.56)ng/L respectively,P<0.01],level of nitric oxide in blood and activity of nitric oxide synthase in aorta were significantly lower (3.06±0.83)nmol/L vs (5.06±0.76)nmol/L,(5.29±1.17) U/mg protein vs (7.75±1.07)U/mg protein respectively,P< 0.01] in the methionine group.Immunohistochemistry showed less expression of von Willebrand Factor and scanning electron microscopy showed contraction of endothelial cells and unevenness and denudation of endothelium in methionine group.Conclusion Hyperhomocysteinemia induced by methionine rich diet had injurious effects on endothelial cells,although did not cause hyperplasia of aorta.